This invention relates to a new and improved sleeve or bladder for the use in curing of belts and power transmission belting which may be of the V-type.
Power transmission belts are generally provided with an endless tension core which is generally formed from fabric cord and may at times be formed from stranded metal cables. In the manufacture of such power transmission belts it is essential to maintain a tensional strain on the belt during the curing process to minimize stretch when the belt is in use. The apparatus used to effect the cure of such belts must maintain sufficient radial pressure to effect the proper tensioning during the cure. To cure the V-belts or power transmission belting, the individual endless V-belts are stacked along with spacers into a cylinderical tank or housing which will have an expandable cylindrical bladder or sleeve located radially inwardly thereof such that upon heating of the V-belts and upon pressurization of the bladder, sufficient pressure is exerted radially outwardly to subject the V-belt to an even outward tension during cure. Steam pressure is used to cure the belts and a differential in pressure developes between the outer and inner surfaces of the bladder or sleeve such that leaks develop at the splice of the cylindrical bladder or sleeve which will ruin the production run because there is insufficient pressure exerted radially outwardly by the bladder to effect the proper tensioning of the belt for proper cure and shaping.
The present invention is directed to the improved splice in the expandable cylindrical bladder or sleeve to increase the strength of the splice and thereby increase the life of the curing bladder and reduce the corresponding scrap.